GCN Circular 15905

Subject
GRB 140301A: Swift-XRT refined Analysis
Event
Date
2014-03-02T12:03:17Z (12 years ago)
From
Kim Page at U.of Leicester <klp5@leicester.ac.uk>
K. L. Page (U Leicester) reports on behalf of the Swift-XRT team:

We have analysed 5.9 ks of XRT data for GRB 140301A (Page  et al. GCN
Circ. 15896Loading...
 
 ),  from 92 s to 51.3 ks after the  BAT trigger. The data
comprise 382 s in Windowed Timing (WT) mode with the remainder in
Photon Counting (PC) mode. The enhanced XRT position for this burst was
given by Goad et al. (GCN Circ. 15898Loading...
 
 ).

The late-time light curve (from T0+6.4 ks) can be modelled with  a
power-law decay with a decay index of alpha=0.95 (+0.32, -0.29).

A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index	of 2.01 (+/-0.09). The
best-fitting absorption column is  3.3 (+/-1.0) x 10^21 cm^-2, at a
redshift of 1.416, in addition to the Galactic value of 2.2 x 10^20
cm^-2 (Kalberla et al. 2005). The PC mode spectrum has a photon index
of 2.42 (+0.32, -0.29) and a best-fitting absorption column of 7.2
(+4.1, -3.3) x 10^21 cm^-2. The counts to observed (unabsorbed) 0.3-10
keV flux conversion factor deduced from this spectrum  is 3.0 x 10^-11
(4.8 x 10^-11) erg cm^-2 count^-1. 

A summary of the PC-mode spectrum is thus:
Galactic foreground: 2.2 x 10^20 cm^-2
Intrinsic column:    7.2 (+4.1, -3.3) x 10^21 cm^-2 at z=1.416
Photon index:	     2.42 (+0.32, -0.29)

If the light curve continues to decay with a power-law decay index of
0.95, the count rate at T+24 hours will be 5.8 x 10^-3 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.7 x
10^-13 (2.8 x 10^-13) erg cm^-2 s^-1.

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00589590.

This circular is an official product of the Swift-XRT team.